Method and apparatus for finishing spherical surfaces

ABSTRACT

An apparatus which includes a base frame, a workpiece-supporting rotatable chuck mounted on the base frame, a cross-slide movably mounted on the base frame and a rotatable workhead mounted on one end of the cross-slide. One or more pairs of radially opposed cutting tools are adjustably mounted on the workhead, the axis of rotation of the workhead being normal to the axis of rotation of the workpiece-supporting chuck. Facing tools are also mounted on the opposite end of the cross-slide. A control system is provided to automatically and precisely control the operation of the various tools. The radially opposed cutting tools are adapted to be moved radially inward to engage the rotating workpiece and while so engaging the workpiece, are revolved about the axis of rotation of the workhead thus generating a spherical surface on the workpiece.

United States Patent Adams [54] METHOD AND APPARATUS FOR FINISHING SPHERICAL SURFACES [72] Inventor: Ladd M. Adams, Norman, Okla.

[73] Assignee: Balon Corporation, Oklahoma City,

Okla.

22 Filed: Jan. 18, 1971 21 Appl.No.: 107,344

[52] US. Cl. ..82/l C, 82/12 [51] Int. Cl ..B23b 3/00, B23b 3/28 [58] Field of Search ..82/l, l C, 12

[56] References Cited UNITED STATES PATENTS 1,663,192 3/1928 Compton ..82/ 12 2,250,161 7/1941 Johnson ..82/l2 3,566,722 3/1971 Audet ....82/12 Primary Examiner-Harrison L. Hinson Attorney-Dunlap, Laney, Hessin & Dougherty [451 Oct. 10,1972

[57] ABSTRACT An apparatus which includes a base frame, a workpiece-supporting rotatable chuck mounted on the base frame, a cross-slide movably mounted on the base frame and a rotatable workhead mounted on one end of the cross-slide. One or more pairs of radially opposed cutting tools are adjustably mounted on the workhead, the axis of rotation of the workhead being normal to the axis of rotation of the workpiece-supporting chuck. Facing tools are also mounted on the opposite end of the cross-slide. A control system is provided to automatically and precisely control the operation of the various tools. The radially opposed cutting tools are adapted to be moved radially inward to engage the rotating workpiece and while so engaging the workpiece, are revolved about the axis of rotation of the workhead thus generating a spherical surface on the workpiece.

21 Claims, 13 Drawing Figures PATENTEDm 10 m2 SHEET 1 [IF 6 L we //1/1/E/V7'0P 44.00 M. ADAMS sum u on;

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METHOD AND APPARATUS FOR FINISHING SPHERICAL SURFACES BACKGROUND OF THE INVENTION 2. Description of the Prior Art The prior art discloses a number of apparatus for forming spherical surfaces V on a rotating workpiece. These apparatus generally utilize a single cutting tool mounted on a rotatable tool support which rotates on an axis normal to the axis of the rotating workpiece. The single cutting tool revolves about the axis of rotation of the tool support and traverses the entire surface of the workpiece to be machined.

Such apparatus are restricted in speed, since a single cutting tool is utilized. They are further limited in the size of workpiece that they can satisfactorily handle. Single cutting tool loading on a small diameter workpiece or a workpiece supported by a small diameter mandrel is extremely detrimental to the generation of a smooth finish on the workpiece due to the deflection of the workpiece or mandrel which such loading causes.

SUMMARY OF THE INVENTION The present invention contemplates an apparatus for finishing a generally spherical workpiece. The apparatus comprises a base frame and a rotatable workpiece-supporting chuck mounted on the base frame and adapted for rotation on a horizontal axis. Means for rotating the workpiece-supporting chuck is also provided. A cross-slide is movably mounted on the base frame and adapted for horizontal movement. along a line lying in a plane normal to the axis of rotation of the workpiece-supporting chuck. Means for moving the cross-slide on the base frame is also provided. A workhead is rotatably mounted on the cross slide and adapted to reciprocatingly rotate on an axis normal to the axis of rotation of the rotatable workpiece-supporting chuck. Two cutting tools are slidably mounted on the workhead in opposed relation and are adapted for radial reciprocating movement thereon into and out of engagement with the workpiece. Means for radially reciprocating the two cutting tools on the workhead into and out of engagement with the workpiece is also provided. Means for reciprocatingly rotating the workhead on the axis normal to the axis of rotation of the rotatable workpiecesupporting chuck is also provided.

An object of the present invention is to provide a method and apparatus for forming smooth spherical surfaces on a workpiece with improved speed and effi- 'ciency.

Another object of the present invention is to provide method and apparatus for forming finished spherical surfaces on small diameter workpieces.

A further object of the present invention is to eliminate the deflection of the workpiece during the forming of spherical surfaces thereon.

A still further object of the present invention is to provide method and apparatus to automatically form spherical finished surfaces on a workpiece with no manual labor required.

forming spherical surfaces Still another object of the present invention is to provide apparatus for forming spherical surfaces on a workpiece which is economical in construction and operation.

Other objects and advantages of the present invention will be evident from the following detailed description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view of the apparatus of the present invention mounted on a conventional metal-cutting lathe.

FIG. 2 is a fragmentary front view in elevation of the ball-turning fixture with a portion of the upper slide broken away to more clearly illustrate the attachment of cutting tools thereto.

FIG. 3 is a sectional view of the ball-turning fixture taken substantially along line 3-3 of FIG. 2.

FIG. 4 is a fragmentary rear view in elevation of the ball-turning fixture.

I FIG. 5 is a fragmentary plan view of the ball-facing fixture.

FIG. 6 is a schematic diagram of the control system of the apparatus of the present invention.

FIG. 7A is a schematic diagram illustrating the crossslide and its two actuating cylinders in position No. l or the starting position.

FIG. 7B is a schematic diagram illustrating the crossslide and its two actuating cylinders in position No. 2 or the ball-facing position.

FIG. 7C is a schematic diagram illustrating the crossslide and its two actuating cylinders in position No. 3 or the first ball-turning position.

FIG. 7D is a schematic diagram illustrating the crossslide and its two actuating cylinders in position No. 4 or the second ball-turning position.

FIG. 8 is a perspective view of the apparatus of the present invention in another embodiment.

FIG. 9 is a fragmentary perspective view more clearly illustrating the power cylinders of the embodiment shown in FIG. 1.

FIG. 10 is a tabular graphical illustration showing the conditions of various elements of the present invention at discrete intervals throughout the operating cycle thereof.

FIG. 11 is a fragmentary perspective view more clearly illustrating the power cylinders of the embodiment shown in FIG. 8.

FIGS. 12 and 13 are schematic diagrams which more cleariy illustrate the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and to FIG. 1 in particular, the apparatus of the present invention is generally designated by reference character 10. The apparatus 10 is shown in FIG. I mounted on a metalcutting lathe 12. Two parallel, laterally spaced longitudinal ways 14 are formed on the horizontal bed 16 of the metal-cutting lathe 12. A motor-driven workpiecesupporting device 18 is rotatably mounted on the metal-cutting lathe 12. The workpiece-supporting device 18 is adapted to rotate about a horizontal axis parallel to the longitudinal ways 14. The workpiecesupporting device 18 comprises a workpiece-supporting chuck 20 and an expandible mandrel 22 horizontally supported by the workpiece-supporting chuck.

A generally spherical workpiece 24 is supported by and releasably secured to the expandible mandrel 22. The workpiece 24 is composed of a rigid material, such as bronze or stainless steel, which is formed by a suitable means, such as casting, into a generally spherical shape. The workpiece 24 also has a generally cylindrical hole 26 formed through the center thereof. The workpiece 24 is positioned on the expandible mandrel 22 by sliding the workpiece 24 onto the expandible mandrel 22, the expandible mandrel 22 extending through the cylindrical hole 26 in the workpiece 24. The expandible mandrel 22 is then caused to expand within the cylindrical hole 26 thus securing the workpiece 24 thereto. The rotation of the workpiece-supporting device 18 results, therefore, in the rotation of the workpiece 24 about a horizontal axis parallel to the longitudinal ways 14.

A tool carriage 28 is slidably mounted on the longitudinal ways 14. The tool carriage is adapted for sliding horizontal movement along the longitudinal ways 14. A cross-slide 30 is slidably mounted on the tool carriage 28. The cross-slide 30 is adapted for sliding lateral horizontal movement upon the tool carriage along a line lying in a plane normal to the alignment of the longitudinal ways 14.

A ball-turning fixture is fixedly secured to the first end 32 of the cross'slide 30 and is generally designated by reference character 34. A ball-facing fixture is fixedly secured to the second end 36 of the cross-slide 30 and is generally designated by reference character 38.

FIGS. 2, 3 and 4, illustrate the construction of the ball-turning fixture 34. Referring more particularly to FIG. 3, a base plate 40 is provided to support the ballturning fixture 34 and provide means for fixedly securing the ball-turning fixture 34 to the cross-slide 30. A front support plate 42 is fixedly secured to the front end 44 of the base plate 40. A rear support plate 46 is fixedly secured to the rear end 48 of the base plate 40. A housing 50 interconnects the front support plate 42 and the rear support plate 46. The front end 52 of the housing 50 is fixedly secured, such as by welding, to the front support plate 42. The rear end 54 of the housing 50 is fixedly secured, such as by welding, to the rear support plate 46. The base plate 40, front support plate 42, rear support plate 46 and housing 50 comprise a housing assembly 56 when assembled as described above.

A bore 58 is formed in the housing 50. A counterbore 60 is formed in the front support plate 42 and the housing 50 and is axially aligned with the bore 58. A counterbore 62 is formed in the front support plate 42 and is axially aligned with the bore 58. A counterbore 64 is formed in the rear end 54 of the housing 50 and is axially aligned with the bore 58. A front bearing 66 is mounted in the counterbore 60. A rear bearing 68 is mounted in the counterbore 64. A spindle 70 is rotatably supported by the front bearing 66 and the rear bearing 68. A circular flange 72 is formed on the front end 74 of the spindle 70. A groove 76 is formed in the periphery surface 78 of the flange 72. An O-ring 80 is seated in the groove 76 and sealingly engages the counterbore 62, thus providing a seal between the flange 72 and the front support plate 42. An axial bore 82 is formed in the rear end 84 of the spindle 70. An axial counterbore 86 is formed through the spindle from the front end 74 thereof.

A workhead 88 is axially aligned with'and fixedly secured to the flange 72 by the bolts 90. An axial bore 92 is formed in the workhead 88. A shaft 94 is concentrically journaled within the spindle 70 and the workhead 88. The front end 96 of the shaft 94 is journaled in the bore 92 of the workhead 88. The rear end 98 of the shaft 94 is journaled in the bore 82 of the spindle 70. A front pinion gear 100 is fixedly secured to the front end 96 of the shaft 94. A first rear pinion gear 102 is fixedly secured to the rear end 98 of the shaft 94. A second rear pinion gear 104 is fixedly secured to the rear end 84 of the spindle 70 by a key 106 and a nut 108 threaded on a rear end 84 of the spindle 70. The nut 108 both retains the second pinion gear 104 in proper position on the spindle 70, and secures the spindle 70 in proper axial position within the housing assembly 56.

Referring now more particularly to FIGS. 3 and 4, a first rack 110 is slidably mounted in a horizontal groove 112 formed in the rear support plate 46 and engages the second rear pinion gear 104. A rear plate 114 is secured to the rear support plate 46 by means of a plurality of bolts 116 and slidably secures the first rack 110 in proper position in the groove 112 in the rear support plate 46. A second rack 118 is slidably mounted in a horizontal groove 120 formed in the rear plate 114 and engages the first rear pinion gear 102. The second rack 118 is retained in the groove 120 in the rear plate 114 by a cover plate 122 which is secured to the rear plate 114 by means of two of the abovementioned bolts 116. A dog 124 is fixedly secured to the rear end 98 of the shaft 94.

. Referring now to FIGS. 2 and 3, an upper slide 126 and a lower slide 128 are slidably mounted in the groove 130 formed on the front face 132 of the workhead 88. The upper slide 126 and the lower slide 128 are retained in the groove 130 by a pair of slide-retaining plates 134. The slide-retaining plates 134 are secured to the front face 132 of the workhead 88 by a plurality of bolts 136. A rack 138 is formed on the lower end of the upper slide 126. A rack 140 is formed on the upper end of the lower slide 128. The racks 138 and 140 engage the front pinion gear 100. The front pinion gear 100 synchronizes the sliding movement of the upper and lower slides 126 and 128 in the groove 130. An adjustable stop 142 is threaded into the upper slide 126 and is secured into place by a locking nut 144. The adjustable stop 142 provides a predetermined limit to the radial proximity of the upper and lower slides 126 and 128 in the groove 130.

An upper cutting tool support 146 is fixedly secured to the upper slide 126 by means of a plurality of bolts 148. A lower cutting tool support 150 is fixedly secured to the lower slide 128 by means of a plurality of bolts 148. A first pair of cutting tools 152 is mounted, in radially opposed relation, on the upper cutting tool support 146 and the lower cutting tool support 150 respectively. A second pair of cutting tools 154 is mounted, in radially opposed relation, on the upper cutting tool support 146 and the lower cutting tool support 150 respectively. Each cutting tool 152 and 154 is secured to a respective cutting tool support 146 or 150 by means of a pair of set-screws 156 and is radially adjustable by means of an adjusting screw 158. It should be noted that any number of pairs of opposed cutting tools may be mounted on a workhead 88 if desired, provided sufficient actuation and control means is available for their utilization. It should further be noted that a pair of burnishing tools or rollers may be sub stituted for a pair of cutting tools if desired.

Referring to FIG. 4, a block 160 is fixedly secured to the rear plate 114. An adjusting screw 162 is threaded through the block 160 and a locking nut 164 is threaded on the adjusting screw 162. A cylindermounting plate 166 is fixedly secured to one side of the housing assembly 56. One end of each of a pair of stand-offs 168 is fixedly secured to the cylinder-mounting plate 166. A main power cylinder 170 is fixedly secured to the opposite ends of the pair of stand-offs 168. One end of each of a pair of stand-offs 172 is fixedly secured to the cylinder-mounting plate 166. A tool relief cylinder 174 is fixedly secured to the opposite ends of the pair of stand-offs 172.

The main power cylinder 170 is adjustably connected to the first rack 110 by means of a threaded rod 176. The toolrelief cylinder 174 is adjustably connected to the second rod 178. 7

FIG. 9 illustrates the apparatus 180 which moves the cross-slide 30 relative to the tool carriage 28. A frame 182 is fixedly secured to the tool carriage 28 and is supported thereby in a horizontal position. The frame 182 includes a plate 184 fixedly secured by suitable means such as bolts, to the back side 186 of the tool carriage 28. Each of a pair of parallel rails 188 is fixedly secured at one end 190 to the plate 184. Each of the rails 188 is fixedly secured at the opposite end 192 to a cross-plate 194. A pair of independently operable, axially aligned two-way pneumatic cylinders 196 and 198 are carried in a housing 200. The housing 200 comprises a front plate 202, a rear plate 204 and a cylindrical shell 206 fixedly secured at each end thereof respectively to the front plate 202 and the rear plate 204. The housing 200 is adapted for sliding horizontal movement between the parallel rails 188. A first cylinder rod 208 extends from the two-way pneumatic cylinder 196 through the front plate 202 and is fixedly secured to the cross-slide 30. A second cylinder rod 210 extends from the two-way pneumatic cylinder 198 through the rear plate 204 and is fixedly secured to the cross-plate 194.

Referring now to FIG. 5, the ball-facing fixture 38 is rack 118 by means of a threaded shown in plan view mounted on the second end 36 of I justing rod 222 fixedly secured thereto and extending horizontally outwardly therefrom. A counterbore 224 is formed in each end of the bore 214. An O-ring 226 is positioned in each counterbore 224. An end plate 228 is fixedly secured to each end of the body 212 and compressingly and sealingly engages the respective O-ring 226 in the counterbore 224. Each end plate 228 has an aperture 230 formed therethrough in axial alignment with the bore 214. An annular groove 232 is formed in the annular wall 234 of each aperture 230. An O-ring 236 is positioned in each annular groove 232 and sealingly engages the respective adjusting rod 222 extending therethrough. An adjusting nut 238 is threaded on the outer end 240 of each adjusting rod 222. Each adjusting nut 238 is secured in proper position after adjustment by a set-screw 242 threaded therein.

Each of the pistons 220a and 220b has a peripheral groove 244 formed therein. An O-ring 246 is positioned in the respective groove 244 of each piston 220a and 220b sealingly and slidingly engaging the bore 214.

The aforementioned lateral groove 216 comprises a pair of parallel lateral walls 248 which communicate with the bottom side 218 of the lateral groove 216 and extend vertically upwardly therefrom. A pair of facingtool-mounting blocks 250 are positioned in the lateral groove 216 and are supported by the bottom side 218 thereof. Two compressed springs 252 are positioned between the facing-tool-mounting blocks 250. The springs 252 urge the facing-tool-mounting blocks 250 horizontally outward against the respective lateral walls 248.

The lateral groove 216 in the body 212 intersects the bore 214 thus exposing the respective inner ends 254 of the pistons 220a and 220b. Each facing-tool-mounting block 250 is fixedly secured to the inner end 254 of a respective piston 220a and 220b by means of a plurality of threaded cap screws 256. A facing tool 258 is adjustably secured to each facing-tool-mounting block 250 by means of a plurality of threaded cap screws 260. Hydraulic lines 262a and 262b are connected to the opposite ends of the body 212 and communicate with the bore 214 therethrough. The hydraulic fluid, when forced through the lines 262a and 262b, causes the resulting horizontally inward movement of the pistons 220a and 220b respectively, overcoming the urging of the springs 252.

The control system for directing fluid to and from the various cylinders is shown schematically in FIG. 6 and the various components are listed in tabular form in FIG. 10. FIG. 10 alsoillustrates in tabular form the condition of each element of the control system at each phase of a complete cycle. In the manually operated push button valves PB-l and PB-2 the symbol 0 indicates the valve is in an up position, the numeral 1 indicates the valve is in a down position. In the limit valves LV-l through LV10, numeralt) indicates the limit valve is in anTup position, the numeral 1 indicates the limit valve is in a down position. In the spool valves V-l through V-6, the numeral 0 indicates the spool valve is in an up position and the numeral 1 indicates the spool valve is in a down position. In the pulse valves, PV-1, PV-2, PV-3, PV-4 and PV-S, the numeral 0 indicates the pulse valve is not providing a pulse, the numeral 1 indicates the pulse valve is providing a pulse. In the check valves SV-l through SV-6, the numeral 0 indicates the check valve is idle at that particular point in time, numeral l indicates the check valve is functioning to check air flow in a particular direction. In the cylinders 170, 174, 196, 198, 220a and 220b, the letter E indicates the cylinder is extended,

and the letter R indicates the cylinder is retracted. The combination E/R indicates the cylinder is moving from an extended position to a retracted position. The symbol R/E indicates the cylinder is moving from a retracted position to an extended position.

To best understand the operation of the present invention, the schematic diagram in FIG. 6 should be read in combination with the tabular diagram of FIG. 10. Referring now to FIGS. 6 and 10 and more particularly to FIG. 10, phase 1 shows the status of the control system in its starting position or Position No. l. Phases 2 and 3 show the status of the present invention in transition from the start position after the start button 268 has been depressed by the operator. Phase 4 shows the condition of the elements of the control system at Position No. 2, the ball-facing position. Phases 5 through 9 indicate the condition of the elements of the control system during the facing operation and during the transition from Position No. 2 to Position No. 3. Phase 10 illustrates the condition of the elements of the control system in Position No. 3, the first ball-turning position. Phases 11 through 15 illustrate the condition of the various elements of the control system through the first ball-turning operation and the transition from Position No. 3 to Position No. 4, the second ball-turning or finishing position. Phase l6 illustrates the condition of the elements of the control system in Position No. 4. Phases 17 through 20 illustrate the condition of the elements of the control system during the second ball-turning operation and the transition from Position No. 4 back to Position No. 1. Phase 21 illustrates the condition of the various elements of the control system in Position No. 1. It should be noted that the condition of the elements in phase 1 is identical to the condition of the elements in phase 21.

Referring now to FIGS. 6, 7A, 7B, 7C, 7D and 10, when in the start position, the cross-slide 30'is at Position No. l with limit valve LV-l tripped. The pistons 220a and 220b are fully retracted and limit valves LV6 and LV8 are tripped. The main power cylinder 170 is fully extended with limit valve LV-9 tripped. The operator loads a ball casting workpiece 24 on the expandable mandrel 22. The air supply lines 264 and 266 are connected to a source of compressed air.

To start the automatic cycle, the operator depresses the start button 268 which trips valve PB-l downwardly allowing compressed air to pass through open limit valve LV-l and open valve PB1 thus tripping spool valve V-l downwardly. When spool valve V-l is so tripped, the compressed air source is removed from air line 27% and compressed air is passed through spool valve V-l through air line 270a to the rod end of two-way pneumatic cylinder 196, thereby causing the retraction of the first cylinder rod 208. The retraction of the first cylinder rod 208 moves the cross-slide 30 to the ball-facing position or Position No. 2. At this time, limit valve LV-l is released and limit valve LV-2 is depressed. When limit valve LV2 is depressed, compressed air is allowed to pass through air lines to pulse valves PV-3 and PV-4. A pulse of compressed air from pulse valve PV-3 trips spool valve V-3 downward thus allowing compressed air to pass therethrough to oil reservoir 272, thereby pressurizing the oil contained therein. The pressurized oil passes through metering valve 274 in hydraulic line 262a to ball-facing fixture 38 thereby causing piston 220a, with a facing tool 258 attached thereto, to move horizontally inward into a workpiece engaging position. The facing tool 258 attached to piston 220a continues to engage the workpiece 24 until limit valve LV-5 is tripped. A pulse of compressed air from pulse valve PV-4 trips spool valve V-4 downward thus passing compressed air to oil reservoir 276, thereby pressurizing the oil contained therein. The pressurized oil passes from oil reservoir 276 through metering valve 278 and hydraulic line 262b to ball-facing fixture 38 thereby urging piston 220b, with a facing tool 258 attached thereto, horizontally inward into a workpiece engaging position. The facing tool 258 attached to piston 220b continues to engage the workpiece until limit valve LV7 is tripped. When limit valve LVS is tripped, compressed air is passed therethrough and trips spool valve V-3 upwardly, thereby releasing the air pressure in oil reservoir 272 which in turn allows piston 220a to be returned to its starting position by means of the urging of springs 252. When piston 220a reaches its starting position, limit valve LV6 is tripped. When limit valve LV7 is tripped, compressed air is passed therethrough and trips spool valve V-4 upwardly, thereby releasing the air pressure in oil reservoir 276 thus allowing piston 220b to be returned to its start position by means of the urging of springs 252. When piston 220b reaches its start position, limit valve LV8 is tripped.

When both limit valves LV6 and LV8 are tripped, compressed air is passed therethrough to pulse valve PV-2 upwardly thus allowing compressed air from the air supplyto pass through air line 280a to the piston end of cylinder 198, and simultaneously releasing air pressure through air line 280b to the rod end of cylinder 198. Cylinder 198 then extends second cylinder rod 210, which in turn moves the cross-slide 30 to a first workpiece engaging position or Position No. 3, wherein the first pair of cutting tools 152 may engage the rotating workpiece 24 (See FIG. 1). At this point, limit valve LV-3 is tripped. When limit valve LV-3 is tripped, compressed air is passed therethrough through check valve SV-5, to pulse valve PV-S. Pulse valve PV-S passes a pulse of compressed air to spool valve V-5 thereby tripping spool valve V-5 upwardly. When spool valve V-S is so tripped, compressed air is released through air line 282a thereby releasing the air pressure in oil reservoir 284. Air pressure is also released from the rod end of cylinder 174, and oil pressure is released from the piston end of cylinder 170. Simultaneously, compressed air is passed through spool valve V-5 through air line 282b thus pressurizing the rod end of cylinder and the piston end of cylinder 174. The air pressure on the piston end of cylinder 174 causes the tool relief cylinder rod 178 to extend, thus engaging the rotating workpiece 24 with the pair of cutting tools 152. (See FIG. 1) The air pressure on the rod end of cylinder 170 causes the retraction of the main power cylinder rod 176 thus rotating the workhead 88. When cylinder 170 begins to retract, limit valve LV9 is released. The speed of the retraction of cylinder 170 is governed by metering valve MV-4 in hydraulic line 284a which adjustably controls the flow of oil from cylinder 170 through hydraulic line 284a into oil reservoir 284.

As shown in FIG. 4, when cylinder 170 retracts, rack 110 moves in the direction of arrow 111 and rotates pinion 104 in the direction of arrow 105. This rotation of pinion 104 causes rotation of the spindle 70, the workhead 88 and the shaft 94 in the same direction. When the dog 124 abuts the adjusting screw 162, the shaft 94, to which the dog 124 is fixedly secured, is denied further rotation along with the spindle 70 and shaft 94 and is caused to rotate in a direction opposite to the arrow 105 relative to the spindle 70, thereby overriding the force of cylinder 174 and the resultant radially inward urging of the cutting tools"152.This counterrotation causes the gradual retraction of the cutting tools 152 from the rotating workpiece 24. By setting the adjusting screw 162 properly, a smooth blending of the radii cut on the workpiece by the respective cutting tools 152 is obtained.

When cylinder 170 is fully retracted, limit valve LV-10 is tripped. When limit valve LV-10 is tripped, compressed air passes therethrough through check valve SV-6, and trips spool valve V- downwardly. When spool valve V-S is so tripped, compressed air is passed therethrough through air line 282a to the oil reservoir 284 and to the rod end of cylinder 174. The pressurized oil in oil reservoir 284 flows through hydraulic line 284a and metering valve MV-3 to the piston end of cylinder 170 thereby extending 170, and rotating the workhead 88 in the opposite direction. The speed of the extension of cylinder 170 is adjustably controlled in metering valve MV-3. When cylinder 170 is fully extended, limit valve LV-9 is tripped. The compressed air introduced into the rod end of cylinder 174 causes the resulting retraction of rod 178.

When limit valve LV-9 is tripped, compressed air is passed therethrough to pulse valve PV-1. Pulse valve PV-l provides a compressed air pulse through check valve SV-2 to trip spool valve V-1 upwardly. When spool valve V-l is so tripped, compressed air is passed therethrough through air line 270b to the piston end of cylinder 196, thereby moving the cross-slide 30 from Position No. 3 to a second workpiece engaging position of Position No. 4. As cross-slide 30 leaves Position No. 3, limit valve LV-3 is released. As cross-slide 30 reaches Position No. 4, limit valve LV-4 is tripped. When limit valve LV-4 is tripped, compressed air is passed therethrough and trips spool valve V-6 upwardly against spring urging. Simultaneous with the upward tripping of spool valve V-6, the compressed air passing through limit valve LV4 also passes through check valve SV-S to pulse valve PV-S. Pulse valve PV-5 in turn provides a compressed air pulse to spool valve V-S thereby tripping spool valve V-S upwardly. When spool valve V-S is tripped upwardly, compressed air is passed therethrough through air line 282b to the piston end of cylinder 174 and to the rod end of cylinder 170. Simultaneously, air pressure is released from air line 282a and oil reservoir 284. The air pressure in air line 282b causes the extension of cylinder 174, and the retraction of cylinder 170. The extension of cylinder 174 causes the second pair of cutting tools 154 to engage the rotating workpiece 24. See FIG. 1. The retraction of the cylinder 170 causes the rotation of workhead 88.

As shown in FlG. 4, when cylinder 170 retracts, rack 110 moves in the direction of arrow 111 and rotates pinion 104in the direction of arrow 105. This rotation of pinion 104 causes rotation of the spindle 70, the workhead 88 and the shaft 94 in the same direction. When the dog 124 abuts the adjusting screw 162, the shaft 94, to which the dog 124 is fixedly secured, is denied further rotation along with the spindle and shaft 94 and is caused to rotate in a direction opposite to the arrow relative to the spindle 70, thereby overriding the force of cylinder 174 and the resultant radially inward urging of the cutting tools 152. This counterrotation causes the gradual retraction of the cutting tools 152 from the rotating workpiece 24. By setting the adjusting screw 162 properly, a smooth blending of the radii cut on the workpiece by the respective cutting tools 152 is obtained.

When cylinder begins its retraction, limit valve LV-9 is released. When cylinder 170 is fully retracted, limit valve LV-10 is tripped. When limit valve LV-10 is tripped, compressed air is passed therethrough, through check valve SV-6, spool valve V-6 and check valve SV-l to trip spool valve V-2 downwardly. The compressed air passing through limit valve LV-lO and check valve SV-6 simultaneously trips spool valve V-5 downwardly. When spool valve V-S is sotripped, compressed air is passed therethrough air line 282a to oil reservoir 284 and to the rod end of cylinder 174. The compressed air introduced into oil reservoir 284 pressurizes the oil contained therein and forces it through hydraulic line 284a to the piston end of cylinder 170, thereby extending cylinder 170 and rotating the workhead 88 in the opposite direction. The compressed air passing through air line 282a to the rod end of cylinder 174 causes the retraction of cylinder 174 with a resulting retraction of the second pair of cutting tools 154 from engagement with the rotating workpiece 24, see FIG. 1. The compressed air passing through spool valve V-2 continues through air line 28% to the rod end of cylinder 198. The air pressure on the rod end of cylinder 198 causes the retraction thereof which in turn moves the cross-slide 30 from Position No. 4 to Position No. 1 thereby releasing limit valve LV-4 and tripping limit valve LV-l. When limit valve LV-4 is released, air pressure is removed from spool valve V-6 which is then allowed to return to its normal downward state by means of internal spring urging. When cylinder 170 is fully extended, limit valve LV-9 is tripped. When limit valve LV-9 is tripped, compressed air is passed therethrough to pulse valve PV-l. Pulse valve PV-l provides a compressed air pulse, through check valve SV-2, to trip spool valve V-1 upwardly. After spool valve V-l isjso tripped, compressed air is allowed to pass through spool valve V-1 through air line 270b to the piston end of cylinder 196 thereby retaining cylinder 196 in a fully extended position. The present invention has now completed a complete operating cycle, and upon removal of the finished workpiece and installation of a new unfinished workpiece, is in proper condition to begin the machining of the new unfinished workpiece upon the pressing of the start button 268 by the operator.

An emergency stop capability is provided in the present invention. This capability allows the operator to stop the operation at any point by pressing the emergency stop button 285. The depression of emergency stop button 285 by the operator, trips valve PV-2 and causes compressed air to be passed therethrough, through check valve SV-2, to trip spool valve V-l upwardly. When spool valve V-l is so tripped, air pressure is released from air line 270a and compressed air is passed therethrough through air line 270b to the piston end of cylinder 196 thus fully extending cylinder 196. The depression of the emergency stop button 285 causes compressed air to be passed through a valve PB-2 and check valve SV-l to trip spool valve V-2 downwardly. The downward tripping of spool valve V-2 releases air pressure from air line 280a and allows compressed air to pass therethrough through air line 28% to the rod end of cylinder 198 thus causing the full retraction of cylinder 198. The depression of the emergency stop button 285 also causes compressed air to pass through valve PB-2 and check valve SV-3 to trip spool valve V-3 upwardly. This tripping of spool valve V-3 removes the compressed air source to oil reservoir 272 thereby releasingthe hydraulic pressure on piston 220a which is then returned to its start position through the urging of springs 252. Compressed air is also passed through emergency stop valve PV-2 through check valve SV-4 to trip spool valve V-4 upwardly. The upward tripping of spool valve V-4 removes the compressed air source from oil reservoir 276 thereby releasing the hydraulic pressure on piston 2201; allowing piston 220b to be urged to its start position by springs 252. When pistons 220a and 220b have both returned to their start positions, limit valves LV-6 and LV-S are tripped. Compressed air passed through the emergency stop valve PV-2 is also directed through check valve SV-6 to spool valve V- thus tripping spool valve V-5 downwardly. This tripping of spool valve V-5 removes the compressed air source from air line 282b. Compressed air is then passed through spool valve V-5 through air line 282a to oil reservoir 284 and to the rod end of cylinder 174. Oil from oil reservoir 284 passes through hydraulic line 284a and through metering valve MV-3 to the piston end of cylinder 170 thereby causing the full extension of cylinder 170. When cylinder C-5 170 is fully extended limited valve LV-9 is tripped. When limit valve LV-9 is tripped, compressed air is passed therethrough to pulse valve PV-l. Pulse valve PV-l provides a compressed air pulse to spool valve V-l thus tripping spool valve V-l upwardly. This upward tripping of spool valve V-l allows compressed air to pass therethrough into air line 270b to the piston end of cylinder 196 to retain cylinder 196 in its fully extended position. As is readily apparent, the use of the emergency stop valve overrides all automatic controls of the present invention and returns the system to the start position or Position No. 1.

SUMMARY OF THE OPERATION OF THE PREFERRED EMBODIMENTS In summary, the operation of the present invention comprises the following steps. First, a roughly spherical ball casting workpiece 24 is supported and rotated by a workpiece-supporting device 18. Next, the ball-facing fixture 38 is automatically indexed to a ball-facing position where the facing tools 258 are caused to engage the rotating workpiece 24 and alternately to retract therefrom. FIG. 12 more clearly illustrates the engagement of the workpiece 24 by the facing tools 258. After the facing tools 258 are retracted from engagement with the workpiece 24, the ball-facing fixture 38 is automatically indexed away from the workpiece 24 and the ball-turning fixture 34 is automatically indexed into position for the first spherical cutting operation on the workpiece 24 at which time the first pair of opposed cutting tools 152 is caused to engage the rotating workpiece 24 while sumultaneously being revolved about an axis normal to the axis of rotation of the workpiece 24. FIG. 13, more clearly illustrates the engagement of the workpiece 24 by the cutting tools 152, the cutting tools 152 being revolved in the direction of arrows 105. The cutting tools 152 are then retracted from engagement with the workpiece 24 and revolved in the opposite direction to their starting position and the ball-turning fixture 34 is automatically indexed into position for the second finishing spherical cut on the workpiece 24. At this time, the second pair of opposed cutting tools 154 is caused to engage the rotating workpiece 24 in a manner identical to that described above for the first pair of cutting tools 152. On completion of the second or finishing cut, the cutting tools 154 are retracted from engagement with the workpiece 24 and revolved back to their starting position and the ball-turning fixture 34 is automatically indexed back to its starting position. The cycle is then complete and the finished valve ball may be removed from the workpiece-supporting device 18.

DESCRIPTION OF THE EMBODIMENT OF FIG. 8

FIG. 8 illustrates another embodiment of the present invention. In this embodiment, the apparatus of the present invention is fixedly secured to the table 286 of a knee type horizontal milling machine 288. Fixedly secured to the table 286 is a frame 290. A slightly modified ball-turning fixture 34a is slidably secured to the frame 290 near the first end thereof 292, and is adapted to slide lengthwise thereon. A slightly modified ball-facing fixture 38a is slidably secured to the frame 290 near the second end thereof 294, and is also adapted to slide lengthwise thereon. A modified motordriven workpiece-supporting device 18a is rotatably mounted on the horizontal milling machine 288. The workpiece-supporting device 18a is adapted to rotate about a horizontal axis lying in a plane perpendicular to the line along which the ball-turning fixture 34a in the ball-facing fixture 38a slides on the frame 290.

FIG. 11 illustrates a slightly modified apparatus a which moves the ball-turning fixture 34a lengthwise on the frame 290. A frame 182a is fixedly secured to the frame 290 and is supported thereby in a horizontal position. The table 286 of the horizontal milling machine further assists in supporting the frame 182a in the horizontal position. The frame 182a includes a plate 184a fixedly secured to the back side 296 of the frame 290. Each of a pair of parallel rails 188a is fixedly secured at one end 190a to the plate 184a. Each of the rails 188a is fixedly secured at the opposite end 192a to a cross-plate 194a. A pair of axially aligned two-way pneumatic cylinders 196a and 198a are carried in a housing 200a. The housing 200a comprises a front plate 202a, a rear plate 204a and a cylindrical shell 206a fixedly secured at each end thereof, respectively to the front plate 202a and the rear plate 204a. The housing 200a is adapted for sliding horizontal through the rear plate 204a and is fixedly secured to the cross-plate 194a."

- As shown in FIG. 8, a two-way pneumatic cylinder 298 is fixedly secured to the second end 294 of the frame 290. A cylinder rod 300 extends outwardly from the twoway pneumatic cylinder 298 and is fixedly secured to the ball-facing fixture 38a. When the twoway pneumatic cylinder 298 is extended and retracted the ball-facing fixture 38a is caused to move slidingly lengthwise on the frame 290. When the two-way pneumatic cylinder 298 is fully extended, the ball-facing fixture is in proper position for the facing tools 258 to engage the workpiece 24. When the two -way pneumatic cylinder is fully retracted, the ball-facing fixture 38a is moved back out of the workpiece engaging position.

OPERATION OF THE EMBODIMENT OF FIG. 8

In the alternate embodiment of the present invention, it is possible to simultaneously perform a facing operation and a turning operation on the workpiece 24. This is possible because the ball-facing fixture 38a and the ball-turning fixture 34a are adapted to be slidingly moved on the frame 290 independently of one another. The ball-facing fixture 38a is moved into workpiece engaging position when the two-way pneumatic cylinder 298 is fully extended. When in the workpiece engaging position, the operation of the ball-facing fixture 38a is the same as described above and need not be recited again. When the ball-facing fixture 38a has completed its cutting operation, the two-way pneumatic cylinder 298 retracts and the ball-facing fixture 38a is slidingly moved along the frame 290 out of workpiece engaging position.

The ball-turning fixture 34a also performs its cutting functions as described above. The ball-turning fixture 34a is in its start position when two-way pneumatic cylinder 196a is fully retracted and two-way pneumatic cylinder 198a is fully retracted. The ballturning fixture 34a is in position to make a first cut on the rotating workpiece 24 when two-way pneumatic cylinder 196a is fully retracted and two-way pneumatic cylinder 198a is fully extended. The ball-turning fixture 34a is in position to make a second cut on the workpiece 24 when two-way pneumatic cylinder 196a is fully extended and two-way pneumatic cylinder 198a is fully retracted. The ball-turning fixture 34a is in position to make a third cut on the workpiece 24 when the two-way pneumatic cylinder 196a is fully extended and two-way pneumatic cylinder 198a is also fully extended. In order for the ball-turning fixture 34a to make a third cut on the workpiece 24, an additional pair of cutting tools 154a must be mounted on the respective cutting tools supports 146a and 150a. The third pair of cutting tools 1540 may be cutting, burnishing, or polishing-tools.

It is obvious that the alternate embodiment described herein, provides additional flexibility and speed in completing a finished workpiece. The increase in speed is provided by the additional two-way pneumatic cylinder 298a for independently moving the ball-facing fixture 38a into and out of workpiece engaging position, while the ball-turning fixture 34a is simultaneously performing its own functions. The additional flexibility is further provided by the third cutting position which the ball-turning fixture 34a can assume.

From the foregoing, it will be apparent that the present invention provides novel methods and apparatus for forming a finished spherical surface on a generally spherical workpiece. Changes may be made in the combination and arrangement of parts or elements and steps or procedures as heretofore set forth in the specification and shown in the drawings without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

1. An apparatus for finishing a generally spherical workpiece into a valve ball, comprising:

a base frame;

a workpiece-supporting device rotatably mounted on the base frame, said workpiece-supporting device being adapted to rotate the work-piece about the axis of rotation of the workpiece-supporting device;

means for rotating the workpiece-supporting device;

a workhead rotatably carried by the base frame, said workhead being adapted for reciprocating movement along a line generally normal to the axis of rotation of the workpiece-supporting device for reciprocating rotation about an axis normal to the axis of rotation of the workpiece-supporting device;

means for reciprocatingly moving the workhead along a line generally normal to the axis of rotation of the workpiece-supporting device;

means 1 for reciprocatingly rotating the workhead about its axis of rotation;

a pair of cutting tools movably mounted on the work head in radially opposed relation, the pair of cutting tools being adapted for radial reciprocating movement on the workhead alternately into and out of engagement with the workpiece; and

means for radially reciprocating the pair of cutting tools on the workhead alternately into and out of engagement with the workpiece.

2. An apparatus as defined in claim 1 characterized further to include:

a first facing tool slidably carried by the base frame;

and

means for reciprocating the first facing tool along a line parallel to the axis of rotation of the workpiece-supporting device alternately into and out of engagement with the workpiece.

3. A lathe as defined in claim 2 characterized further to include:

a'second facing tool slidably carried by the base frame; and

means for reciprocating the second facing tool along a line parallel to the axis of rotation of the workpiece-supporting device alternately into and out of engagement with the workpiece.

4. A lathe as defined in claim 3 characterized further to include:

means for controlling the reciprocation of the first .and second facing tools so that said first and second facing tools may be automatically indexed to engage the workpiece and, alternately, to retract therefrom;

means for controlling the radial reciprocating movement of the pair of cutting tools movably mounted on the workhead so that said cutting tools may be automatically indexed substantially simultaneously to engage the workpiece and, alternately, to simultaneously retract therefrom; and

means for controlling the rotation of the workhead so that each of the pair of cutting tools mounted thereon traces a limited arc while engaging the workpiece.

5. In combination with a metal-cutting lathe of the type having a base frame, laterally spaced longitudinal ways'mounted on the base frame, a motor-driven rotary workpiece-supporting device adapted to rotate about an axis parallel to the longitudinal ways, and a tool carriage mounted on the ways adapted for longitudinal movement on the longitudinal ways, an apparatus for finishing a generally spherical workpiece supported by the workpiece-supporting device into a valve ball, comprising:

a first cross-slide slidably mounted on the tool carriage and adapted for lateral reciprocating movement thereon along a line normal to the longitudinal ways;

means for laterally reciprocating the first cross-slide on the tool carriage;

a first facing tool slidably mounted on the first crossslide and adapted for reciprocating movement thereon along a line parallel to the longitudinal ways;

means for reciprocating the first facing tool on the first cross-slide alternately into and out of engagement with the workpiece;

a second cross-slide slidably mounted on the tool carriage and adapted for lateral reciprocating movement thereon along a'line normal to the longitudinal ways;

means for laterally reciprocating the second crossslide on the tool carriage;

a workhead rotatably mounted on the sec'ond crossslide and adapted to reciprocatingly rotate on an axis normal to the axis of rotation of the rotary workpiece-supporting device;

a pair of cutting tools slidably mounted on'the workhead in opposed relation and adapted for radial reciprocating movement thereon alternately into and out of engagement with the workpiece;

means for radially reciprocating the pair of cutting tools on the workhead alternately into and out of engagement with the workpiece; and

means for reciprocatingly rotating the workhead about an axis normal to the axis of rotation of the rotary workpiece-supporting chuck.

6. A metal-cutting lathe as defined in claim charac terized further to include:

a second facing tool slidably mounted on the first cross-slide and adapted for reciprocating movement thereon along a line parallel to the longitudinal ways; and

means for reciprocating the second facing tool on the first cross-slide into and out of engagement with the workpiece.

7. A metal-cutting lathe as defined in claim 6 characterized further to include:

means for controlling the lateral reciprocating movement of the first cross-slide alternately into and out 5 of a workpiece-engaging position; and

means for controlling the reciprocating movement of the first and second facing tools on the first crossslide alternately into and out of engagement with the workpiece. 8. A metal-cutting lathe as defined in claim 5 characterized further to include:

means for controlling the lateral reciprocating movement of the second cross-slide alternately into and out of workpiece-engaging position;

means for controlling the radial reciprocating movement of the pair of opposed cutting tools on the workhead; and

means for controlling the reciprocating rotation of the workhead so that each of the pair of opposed cutting tools mounted thereon, traces a limited arc while engaging the workpiece.

9. In combination with a metal-cutting lathe of the type having a base frame, laterally spaced longitudinal ways mounted on the base frame, a motor-driven rotary workpiece-supporting device adapted to rotate about an axis parallel to the longitudinal ways, and a tool carriage mounted on the longitudinal ways, an apparatus for finishing a generally spherical workpiece supported by the workpiece-supporting device comprising:

a cross-slide slidably mounted on the tool carriage and adapted for lateral reciprocating movement thereon along a line normal to the longitudinal ways;

means for laterally reciprocating the cross-slide on the tool carriage alternately into and out of workpiece-engaging positions;

a workhead rotatably mounted on the cross-slide and adapted to reciprocatingly rotate about an axis normal to the axis of rotation of the rotary workpiece-supporting device;

a pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon into and out of engagement with the workpiece;

means for radially reciprocating the pair of cutting tools on the workhead alternately into and out of engagement with the workpiece; and

means for reciprocatingly rotating the workhead about an ,axis normal to the axis of rotation of the rotary workpiece-supporting device.

10. A lathe as defined in claim 1 characterized further to include:

a second pair of cutting tools movably mounted on the workhead in radially opposed relation and adapted for radial reciprocating movement thereon; and

means for radially reciprocating the second pair of cutting tools alternately into and out of engagement with the workpiece.

11. A metal-cutting lathe as defined in claim 5 characterized further to include:

a second pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon alternately into and out of engagement with the workpiece; and

means for radially reciprocating the second pair of cutting tools on the workhead alternately into and out of engagement with the workpiece.

12. A lathe as defined in claim 1 characterized further to include:

at least one additional pair of cutting tools movably mounted on the workhead in radially opposed relation and adapted for radial reciprocating movement thereon; and

means for radially reciprocating each additional pair of cutting tools alternately into and out of engagement with the workpiece. 13. A metal-cutting lathe as defined in claim 5 characterized further to include:

at least one additionalpair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon alternately into and out of engagement with the workpiece; and 1 means for radially reciprocating each additional pair of cutting tools on the workhead alternately into and out of engagement with the workpiece.

14. In combination with aconventional metal-cutting lathe of the type having a rotatable workpiece-supporting device, an apparatus for finishing a generally spherical work-piece supported by the workpiece-supporting device, into a valve ball, comprising:

a cross-slide having first and second end portions laterally slidably mounted on the lathe;

means for laterally reciprocating the cross-slide with respect to the lathe;

a first facing tool slidably carried tion of the cross-slide; means for reciprocating the first facing tool with respect to the cross-slide; i a workhead rotatably mounted on the second end portion of the cross-slide, the workhead being adapted to rotate in a plane normal to the plane of rotation of the rotatable workpiece-supporting by the first end pordevice;

a pair of cutting tools movable mounted upon the workhead in radially opposed relation;

means for radially moving the pair of cutting tools alternately closer together and farther apart; and means for rotating the workhead.

15. A lathe as defined in claim 14 characterized further to include:

a second facing tool slidably carried by the first end portion of the cross-slide; and

means for reciprocating the second facing tool with respect to the cross-slide.

16. In combination with a metal-cutting milling machine of thetype having a base frame, a horizontally movably work-supporting table mounted on the base frame, and a motor-driven workpiece-supporting device rotatably mounted on the base frame, an apparatus for finishing a generally spherical workpiece supported by the workpiece-supporting device into a valve ball, comprising:

a workhead movably mounted on the work-supporting table and adapted to reciprocatingly rotate along the axis of rotation of the workhead;

a pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement on the workhead into and out of engagement with the workpiece;

means for radially reciprocating the pair of cutting tools on the workhead into and out of engagement with the workpiece; and

means for reciprocatingly rotating the workhead about an axis normal to the axis of rotation of the workpiece-supporting device.

17. An apparatus as defined in claim 16 characterized further to include:

a first facing tool movably mounted on the work-supporting table and adapted for reciprocating movement thereon along a line parallel to the axis of rotation of the workhead into and out of engagement with the workpiece; and

means for reciprocatingly moving the first facing tool on the work-supporting table.

18. An apparatus as defined in claim 17 characterized further to include:

a second facing tool movably mounted on the worksupporting table and adapted for reciprocating movement thereon along a line parallel to the axis of rotation of the workhead into and outof engagement with the workpiece; and

means for reciprocatingly moving the second facing tool on the work-supporting table.

19. An apparatus as defined in claim 14 characterized further to include:

at least one additional pair of cutting tools movably mounted on the workhead in radially opposed relation, each additional pair of cutting tools being adapted for radial reciprocating movement on the workhead into and out of engagement with the workpiece; and

means for radially moving the additional pairs of cutting tools alternately closer together and farther apart.

20. A method for automatically turning precision spherical ball members for use in ball valves and the like from a generally spherical workpiece, comprising the steps of:

rotating the workpiece about an axis of rotation by means of a workpiece-supporting device;

indexing a pair of facing tools from a starting position to a workpiece-engaging position;

engaging the workpiece with the pair of facing tools;

facing the workpiece with the pair of facing tools;

retracting the pair of facing tools from the workpiece;

indexing the pair of facing toolsfrom the workpieceengaging position to the starting position;

indexing a workhead from a starting position to a first workpiece-engaging position;

engaging the workpiece with a first pair of opposed cutting tools slidably mounted on the workhead;

rotating the workhead about its axis of rotation in one direction a predetermined amount;

revolving the first pair of opposed cutting tools about the axis of rotation of the workhead in the one direction the predetermined amount;

performing a first cut on the workpiece with the first pair of opposed cutting tools as the first pair of opposed cutting tools is revolved about the axis of rotation of the workhead;

retracting the first pair oi opposed cutting tools from engagement with the workpiece;

rotating the workhead the opposite direction back to the first workpiece-engaging position;

indexing the workhead from the first workpiece-engaging position to a second workpiece-engaging position;

engaging the workpiece with a second pair of opposed cutting tools slidably mounted on the workhead;

rotating the workhead about its axis of rotation in one direction a predetermined amount;

revolving the second pair of opposed cutting tools about the axis of rotation of the workhead in the one direction the predetermined amount;

performing a second cut on the workpiece with the second pair of opposed cutting tools as the second pair of opposed cutting tools is revolved about the axis of rotation of the workhead;

retracting the second pair of opposed cutting tools from the workpiece;

rotating the workhead the opposite direction back to the second workpiece-engaging position;

indexing the workhead from the second workpieceengaging position to the starting position;

stopping the rotation of the workpiece; and

removing the finished workpiece from the workpiece-supporting device.

21. A method of automatically turning precision spherical ball members for use in ball valves and the like from a generally spherical workpiece, comprising the steps of:

rotating the workpiece about an axis of rotation by means of a workpiece-supporting device;

indexing a workhead from a starting position to a workpiece-engaging position;

engaging the workpiece with a pair of opposed cutting tools slidably mounted on the workhead;

rotating the workhead about its axis of rotation in one direction a predetermined amount;

revolving the pair of opposed cutting tools about the axis of rotation of the workhead in the one direction the predetermined amount;

performing a cut on the workpiece with the pair of opposed cutting tools as the pair of opposed cutting tools is revolved about the axis of rotation of the workhead;

retracting the pair of opposed cutting tools from engagement with the workpiece;

rotating the workhead the opposite direction back to the workpiece-engaging position;

indexing the workhead from the workpiece-engaging position to the starting position;

stopping the rotation of the workpiece; and

removing the workpiece from the workpiece-supporting device. 

1. An apparatus for finishing a generally spherical workpiece into a valve ball, comprising: a base frame; a workpiece-supporting device rotatably mounted on the base frame, said workpiece-supporting device being adapted to rotate the work-piece about the axis of rotation of the workpiecesupporting device; means for rotating the workpiece-supporting device; a workhead rotatably carried by the base frame, said workhead being adApted for reciprocating movement along a line generally normal to the axis of rotation of the workpiece-supporting device for reciprocating rotation about an axis normal to the axis of rotation of the workpiece-supporting device; means for reciprocatingly moving the workhead along a line generally normal to the axis of rotation of the workpiecesupporting device; means for reciprocatingly rotating the workhead about its axis of rotation; a pair of cutting tools movably mounted on the workhead in radially opposed relation, the pair of cutting tools being adapted for radial reciprocating movement on the workhead alternately into and out of engagement with the workpiece; and means for radially reciprocating the pair of cutting tools on the workhead alternately into and out of engagement with the workpiece.
 2. An apparatus as defined in claim 1 characterized further to include: a first facing tool slidably carried by the base frame; and means for reciprocating the first facing tool along a line parallel to the axis of rotation of the workpiece-supporting device alternately into and out of engagement with the workpiece.
 3. A lathe as defined in claim 2 characterized further to include: a second facing tool slidably carried by the base frame; and means for reciprocating the second facing tool along a line parallel to the axis of rotation of the workpiece-supporting device alternately into and out of engagement with the workpiece.
 4. A lathe as defined in claim 3 characterized further to include: means for controlling the reciprocation of the first and second facing tools so that said first and second facing tools may be automatically indexed to engage the workpiece and, alternately, to retract therefrom; means for controlling the radial reciprocating movement of the pair of cutting tools movably mounted on the workhead so that said cutting tools may be automatically indexed substantially simultaneously to engage the workpiece and, alternately, to simultaneously retract therefrom; and means for controlling the rotation of the workhead so that each of the pair of cutting tools mounted thereon traces a limited arc while engaging the workpiece.
 5. In combination with a metal-cutting lathe of the type having a base frame, laterally spaced longitudinal ways mounted on the base frame, a motor-driven rotary workpiece-supporting device adapted to rotate about an axis parallel to the longitudinal ways, and a tool carriage mounted on the ways adapted for longitudinal movement on the longitudinal ways, an apparatus for finishing a generally spherical workpiece supported by the workpiece-supporting device into a valve ball, comprising: a first cross-slide slidably mounted on the tool carriage and adapted for lateral reciprocating movement thereon along a line normal to the longitudinal ways; means for laterally reciprocating the first cross-slide on the tool carriage; a first facing tool slidably mounted on the first cross-slide and adapted for reciprocating movement thereon along a line parallel to the longitudinal ways; means for reciprocating the first facing tool on the first cross-slide alternately into and out of engagement with the workpiece; a second cross-slide slidably mounted on the tool carriage and adapted for lateral reciprocating movement thereon along a line normal to the longitudinal ways; means for laterally reciprocating the second cross-slide on the tool carriage; a workhead rotatably mounted on the second cross-slide and adapted to reciprocatingly rotate on an axis normal to the axis of rotation of the rotary workpiece-supporting device; a pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon alternately into and out of engagement with the workpiece; means for radially reciprocating the pair of cutting tools on the workhead alternately into and out of engagement with the workPiece; and means for reciprocatingly rotating the workhead about an axis normal to the axis of rotation of the rotary workpiece-supporting chuck.
 6. A metal-cutting lathe as defined in claim 5 characterized further to include: a second facing tool slidably mounted on the first cross-slide and adapted for reciprocating movement thereon along a line parallel to the longitudinal ways; and means for reciprocating the second facing tool on the first cross-slide into and out of engagement with the workpiece.
 7. A metal-cutting lathe as defined in claim 6 characterized further to include: means for controlling the lateral reciprocating movement of the first cross-slide alternately into and out of a workpiece-engaging position; and means for controlling the reciprocating movement of the first and second facing tools on the first cross-slide alternately into and out of engagement with the workpiece.
 8. A metal-cutting lathe as defined in claim 5 characterized further to include: means for controlling the lateral reciprocating movement of the second cross-slide alternately into and out of workpiece-engaging position; means for controlling the radial reciprocating movement of the pair of opposed cutting tools on the workhead; and means for controlling the reciprocating rotation of the workhead so that each of the pair of opposed cutting tools mounted thereon, traces a limited arc while engaging the workpiece.
 9. In combination with a metal-cutting lathe of the type having a base frame, laterally spaced longitudinal ways mounted on the base frame, a motor-driven rotary workpiece-supporting device adapted to rotate about an axis parallel to the longitudinal ways, and a tool carriage mounted on the longitudinal ways, an apparatus for finishing a generally spherical workpiece supported by the workpiece-supporting device comprising: a cross-slide slidably mounted on the tool carriage and adapted for lateral reciprocating movement thereon along a line normal to the longitudinal ways; means for laterally reciprocating the cross-slide on the tool carriage alternately into and out of workpiece-engaging positions; a workhead rotatably mounted on the cross-slide and adapted to reciprocatingly rotate about an axis normal to the axis of rotation of the rotary workpiece-supporting device; a pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon into and out of engagement with the workpiece; means for radially reciprocating the pair of cutting tools on the workhead alternately into and out of engagement with the workpiece; and means for reciprocatingly rotating the workhead about an axis normal to the axis of rotation of the rotary workpiece-supporting device.
 10. A lathe as defined in claim 1 characterized further to include: a second pair of cutting tools movably mounted on the workhead in radially opposed relation and adapted for radial reciprocating movement thereon; and means for radially reciprocating the second pair of cutting tools alternately into and out of engagement with the workpiece.
 11. A metal-cutting lathe as defined in claim 5 characterized further to include: a second pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon alternately into and out of engagement with the workpiece; and means for radially reciprocating the second pair of cutting tools on the workhead alternately into and out of engagement with the workpiece.
 12. A lathe as defined in claim 1 characterized further to include: at least one additional pair of cutting tools movably mounted on the workhead in radially opposed relation and adapted for radial reciprocating movement thereon; and means for radially reciprocating each additional pair of cutting tools alternately into and out of engagement with the workpiece.
 13. A metal-cutTing lathe as defined in claim 5 characterized further to include: at least one additional pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement thereon alternately into and out of engagement with the workpiece; and means for radially reciprocating each additional pair of cutting tools on the workhead alternately into and out of engagement with the workpiece.
 14. In combination with a conventional metal-cutting lathe of the type having a rotatable workpiece-supporting device, an apparatus for finishing a generally spherical work-piece supported by the workpiece-supporting device, into a valve ball, comprising: a cross-slide having first and second end portions laterally slidably mounted on the lathe; means for laterally reciprocating the cross-slide with respect to the lathe; a first facing tool slidably carried by the first end portion of the cross-slide; means for reciprocating the first facing tool with respect to the cross-slide; a workhead rotatably mounted on the second end portion of the cross-slide, the workhead being adapted to rotate in a plane normal to the plane of rotation of the rotatable workpiece-supporting device; a pair of cutting tools movable mounted upon the workhead in radially opposed relation; means for radially moving the pair of cutting tools alternately closer together and farther apart; and means for rotating the workhead.
 15. A lathe as defined in claim 14 characterized further to include: a second facing tool slidably carried by the first end portion of the cross-slide; and means for reciprocating the second facing tool with respect to the cross-slide.
 16. In combination with a metal-cutting milling machine of the type having a base frame, a horizontally movably work-supporting table mounted on the base frame, and a motor-driven workpiece-supporting device rotatably mounted on the base frame, an apparatus for finishing a generally spherical workpiece supported by the workpiece-supporting device into a valve ball, comprising: a workhead movably mounted on the work-supporting table and adapted to reciprocatingly rotate about and axially reciprocate along an axis normal to the axis of rotation of the workpiece-supporting device; means for axially reciprocating the workhead along the axis of rotation of the workhead; a pair of cutting tools slidably mounted on the workhead in opposed relation and adapted for radial reciprocating movement on the workhead into and out of engagement with the workpiece; means for radially reciprocating the pair of cutting tools on the workhead into and out of engagement with the workpiece; and means for reciprocatingly rotating the workhead about an axis normal to the axis of rotation of the workpiece-supporting device.
 17. An apparatus as defined in claim 16 characterized further to include: a first facing tool movably mounted on the work-supporting table and adapted for reciprocating movement thereon along a line parallel to the axis of rotation of the workhead into and out of engagement with the workpiece; and means for reciprocatingly moving the first facing tool on the work-supporting table.
 18. An apparatus as defined in claim 17 characterized further to include: a second facing tool movably mounted on the work-supporting table and adapted for reciprocating movement thereon along a line parallel to the axis of rotation of the workhead into and out of engagement with the workpiece; and means for reciprocatingly moving the second facing tool on the work-supporting table.
 19. An apparatus as defined in claim 14 characterized further to include: at least one additional pair of cutting tools movably mounted on the workhead in radially opposed relation, each additional pair of cutting tools being adapted for radial reciprocating movement on the workhead into and out of engagement with the workpiece; and means For radially moving the additional pairs of cutting tools alternately closer together and farther apart.
 20. A method for automatically turning precision spherical ball members for use in ball valves and the like from a generally spherical workpiece, comprising the steps of: rotating the workpiece about an axis of rotation by means of a workpiece-supporting device; indexing a pair of facing tools from a starting position to a workpiece-engaging position; engaging the workpiece with the pair of facing tools; facing the workpiece with the pair of facing tools; retracting the pair of facing tools from the workpiece; indexing the pair of facing tools from the workpiece-engaging position to the starting position; indexing a workhead from a starting position to a first workpiece-engaging position; engaging the workpiece with a first pair of opposed cutting tools slidably mounted on the workhead; rotating the workhead about its axis of rotation in one direction a predetermined amount; revolving the first pair of opposed cutting tools about the axis of rotation of the workhead in the one direction the predetermined amount; performing a first cut on the workpiece with the first pair of opposed cutting tools as the first pair of opposed cutting tools is revolved about the axis of rotation of the workhead; retracting the first pair of opposed cutting tools from engagement with the workpiece; rotating the workhead the opposite direction back to the first workpiece-engaging position; indexing the workhead from the first workpiece-engaging position to a second workpiece-engaging position; engaging the workpiece with a second pair of opposed cutting tools slidably mounted on the workhead; rotating the workhead about its axis of rotation in one direction a predetermined amount; revolving the second pair of opposed cutting tools about the axis of rotation of the workhead in the one direction the predetermined amount; performing a second cut on the workpiece with the second pair of opposed cutting tools as the second pair of opposed cutting tools is revolved about the axis of rotation of the workhead; retracting the second pair of opposed cutting tools from the workpiece; rotating the workhead the opposite direction back to the second workpiece-engaging position; indexing the workhead from the second workpiece-engaging position to the starting position; stopping the rotation of the workpiece; and removing the finished workpiece from the workpiece-supporting device.
 21. A method of automatically turning precision spherical ball members for use in ball valves and the like from a generally spherical workpiece, comprising the steps of: rotating the workpiece about an axis of rotation by means of a workpiece-supporting device; indexing a workhead from a starting position to a workpiece-engaging position; engaging the workpiece with a pair of opposed cutting tools slidably mounted on the workhead; rotating the workhead about its axis of rotation in one direction a predetermined amount; revolving the pair of opposed cutting tools about the axis of rotation of the workhead in the one direction the predetermined amount; performing a cut on the workpiece with the pair of opposed cutting tools as the pair of opposed cutting tools is revolved about the axis of rotation of the workhead; retracting the pair of opposed cutting tools from engagement with the workpiece; rotating the workhead the opposite direction back to the workpiece-engaging position; indexing the workhead from the workpiece-engaging position to the starting position; stopping the rotation of the workpiece; and removing the workpiece from the workpiece-supporting device. 